Regions and Availability Zones

Cloud providers run their data centres in regions, separate geographic areas such as Mumbai (ap-south-1) or Hyderabad, and split each region into availability zones (AZs): one or more data centres with their own power, cooling and networking, connected by fast, low-latency links.

Running an application across two or more availability zones keeps it up if one data centre fails. Running in several regions protects against a whole region going down and puts servers closer to users. Data residency rules may also require data to stay in a particular region or country.